Directive radio transmission system



Nov. 24, 1925. 1,562,961 r R. A. HElSlNG DIRECTIVE RADIO TRANSMISSION SYSTEM Filed May 16 1921 f4 Sheets-Sheet 1 v Mrenfak: fiayman'dA fle/ls/nq Nov. 24, 1925- 1,562,961

- R. A. HEISING I DIRECTIVE RADIO TRANSMISSION SYSTEM Filed May 16, 1921 1 4 Sheets- Sheet .2 7

Nov. 24,1925- 1,562,961 R. A. HEiSlNG I DIRECTIVE RADIO TRANSMISSION SYSTEM 4 Sheeias-Sheet 3 7 Filed ma 16. 1921 Nov. 24,1925. 1,562961 R. A.HEl$lNG niiwcnvm mom TRANSMISSION SYSTEM Filed May 16, 1921 4 sheet -she'et' 4 "Patented Nov. 24,1925; T I f 1 f UNITED STATES PATENT ,nAYMoNn A. nmsmo, or MILBURN, New JERSEY, IASSIQNOR :ro wns'rmm ntEc-- 'rmc- COMPANY, mconrona'rnn, OF NEW YORK, n. Y., a conrona'non or new "YORK...

I DIRECTIVE BADIO'TRANSMISSION SYSTEM."

Application filed Kay 16, 1921. Serial No. 470,042. a .T .11 whom it may concem: invention is'to provide a focussing antenna Be it knownthat I, RAYMOND A. Hnrsmo, which will concentrate the radiated energy a citizen of United States of America, residat a distant point. i A i a 7 ing at Milburn, in the county of Essex, State The propagation velocity. of wavein'any vI! of New Jersey, have invented certain new medium is in general the product of its freand useful Improvements in Directive Radio quency and its wave length in that medium. Transmission Systems, of which the follow- In the'case of free electric waves, the propa-- ing is a full, clear, concise, and exact degation velocity is approximately 300,000,000 s i tion. meters per. second. In the case ofguided 10 This invention relates to directive tran'selectric waves, the wave len th and the wave missions of energy and more particularly to propagat on velocity are unctipns. of the methods of and systems for directively electricalconstants ofthe guiding transiniS- radiating and absorbing electric waves. slon conductors. As, given by Heaviside, An object of the present invention is to the wave lengths of a sustained wave over provide a transmission system for radiating a .circuit having uniformly distributed inenergy directively. Another object of the ductance andcapa'city is where a is the wave length, (a is the angular ant wave at a receiving" antenna as to cause velocity or the wave. frequency multiplied by all of the absorbed energy to cumulatively d5 '21v'and S, R, L, and C arerespectively the affect the receiving device. I shunt conductance, series resistance, series. 'According to, the present invention a'radio inductance, and shunt capacity of the cirtransmitting or receiving antennavi's: made cuit per unit length. This wave length evi long with respect to the wave-length of the 7 dently depends upon the magnitudes of these wave to be transmitted .or received. ""It ljlo 4 four electrical characteristics per unit length order to make this antenna behave as, a conof the circuit. By varying these it is posductor of infinite length and thereby avoid sihlc to increase or decrease the wave length the production of a reflected wave, itfis deof the sustained wave and accordingly to sir-able to terminate it in an impedance elevary the wave propagation velocity along ment having an impedance equivalent in'76 I the circuit. If a loaded circuit of this charmagnitude and character to the iterative or F actor is used for radiating or absorbing elec-. surgeimpedance of the antenna itself at the tric waves, the waves, it sustained sine er1niiiatin g point. At intervals correspondwavcs, may b'e'propaga-tcd along the circuit ing to a fraction of'a wave length, thela-nat a. greater velocity than that at which they ten'ua is loaded by inserting'serles capacity no progress in the ether. If a definite small or shunt inductance or both to makeits y part of a transmitting antenna be considwave propagation velocity for the waVQStQ f cred, the energy of the wave proceeding be transferred 'higher'thanthe correspond 7 from that part will be partly propagated ing wave propagation velocity in ether. along the circuit as a guided wave, and'part- Since the energy in a radiating antenna" dea 86' 56 .ly radiated and propagated out through the creases with increasing distance from the surrounding space. The shape of the re- 'source,it is desirable inorder to seeureffthe H sultant wave front in the'ether will be debest results to progressively. 'increase' ,tlie i pendent uponthe relative velocities of wave radiating factor of the antennaandIth1sas a "propagation in the two media; It is, theredone by increasing its height. 90 fox-e, possible to give a radiated wavevari- The invention permits radiation in "one v ously direct-ed fronts depending upon the lateral direction to the substantial exclusion loading'of the' antenna circuit. It is =li-keof radiation in any other by an arrangement .w 1 0 bsorbthe directed radiofparallel antennae. For focussing, on a fixed receiving point the loading of the transmitting antenna may be progressively increased so as to progressively change the direction of-the wave front of the emitted wave. The antenna may also be curved laterally to add to the focussing effect. For multiplex operation,

different frequencies may be focussed at the same or different points by loading the air.

tenna in different manners for waves of each of the different frequencies. I

Other objects of the invention will be apparent upon consideration of the following antennae; Figure 6, a diagram of current I and energy distribution in antennae of the tem depending upon tribution of ty disclosed; Figure 7, the radiating coofiit ient diagram for antennae of this type; Figure 8, a polar diagram showing the disthe radiated wave amplitude in various angular zones; Figure 9, a polar diagram showing the distribution of energyof a modulated carrier wave; Figure 10, an antenna system for neutralizing the directed energy in one direction; Figure 11', an ar rangement of laterally curved antennae for focussing energy at a distant receiving sta- -tion;"Figure 12, a diagram indicating the operation of a second type of focussing sysprogressive change in loading; Figure 13, an antenna arrangement for this second type of system;-Figure 14-, a directive capacity and inductance loading; Figures 15' to 17 illustrate details of loading arrangements applicable to any of the formgolng systems; Figure 18,'a receiving system with a loaded antenna; and Figure 19, a multiplex system for focussing a plurality of different waves.

Referring to Figure 1, a source 1 is .associated with an antenna 2 to supply energy thereto for radiation. Antenna 2 is preferably of a lengthseveral times the wavelength defined in equation 1). This wave length depends upon the inductance and capacity per unit length of the radiating circuit. In loaded telephone lines with inductances, as is the common practice, the wavelength is greatly shortened. In fact, in

loaded line telephone practice, the wave-V lengtlrmultiplied by'the frequency may give a velocity of the order 90,000,000 meters per second instead of 300,000,000 meters per waves of a plurality of capacityv is approximated. exact number of focussing system employing both.

.seriesv inductance, 'duce lower eifectwe serlesmductance per The action of the inductance ance and shunt conductance of the circuit are made zero, equation (1) reduces to From equation (2) it would appear that, with circuits of negligible series resistance and shunt conductance per unit length, either reducing the series inductance per unit length or the shunt capacity per unit length, should increase the wave length and, therefore, increase the velocity at which a given frequency wave is pro agated'along the circuit. This can actua ly be accomplished in several ways it being remembered that the long antenna with its capacity to ground and the return ground conducting path may, if uniform and if properly terminated, be treated as any other alternating current conducting circuit. One simple way to increase the velocity of'the wave propagation is illustrated in Fig. '1 in-which series loading capacities 3 and shunt inductances 6 are inserted in the conducting line and are spaced much in the same manner as are the loading inductances in loaded telephone lines. These loading inductances and capacities should be separated by distances small compared. to a-wave length, so that the effect of uniform distribution of the Although the such elements may vary greatly, it is desirable to use eight or more per unit length. For simplicity only a, few elements -are shown. Theaction of this capacity loading is to introduce series reactance opposite in sign to that of thenatural and accordingly to pro unit length. loading is to positein sign to that of the natural introduce shunt reactance opshunt capacity and hence to produce lower effective J shunt capacity reactance per unit length. It will, of course, be understood that either series capacity loading or shunt inductance loading alone may be used. I

{is has been previously mentioned, a circult of this character of finite length must be properly terminated to avoid havin a wave reflected from the free terminal. A reflected wave produces nodes along the Circuit and introduces complications of various sorts. If the transmitted wave gives directive radiation in the general direction of its transmission the reflected wave will give directive radiation in the oppositedirection- .To eliminate the reflected wave and prevent this reverse transmission, it- 1s only necessary to terminate the line with a proper impedance Z, the value of which may be computed from well known transmission equations.

. Fig. 2 illustrates a modification of the 211- rangement of Fig. '1 1n which series capacity ,loading. 1s employed. Conductor 2 is pro- I factor so as tomaintain the energy radiation as nearly ressively elevated to increase the radiating equal as possible at all points along; the -antennas To maintain the unit shunt capacity constant with increasing.

height a conductor, of'increasing size 19 6111- ploved. An, element of the recurrent net-' fwork'thus formed .is illustrated in Figure '.-3, in whichthe natural series inductance:

and shunt capacity f the conductor, both indicated by dotted lines, constitute. together with the-loading capacity 3 a uniforml s'eceffective shunt capacity of the is accomplished by .line and ground, which are preferably spaced eight or more to the wave length, although in this case as well as in the case of the series capacity 1oad-' ing, a considerablevariations inthis number 'tion of the line.v

Fig. 4 illustrates-another methodgof an" tenna loading whichconsists in reducing. the circuit. This connecting between the loading inductances 6' may be permitted. It-is a well.-knowni fact s that the effective capacity of'a condenser is I reduced by connecting in parallel with. it a antenna of thetype illustrated in Figures 2 and 3, suppose located at terminal 0. An electrical disturbance occurring as an alternation of elecat this point travels along large inductance flheeilective reactance of creased. At a givenfrethe capacity 5 Resistance tends It is accordingly desirable to resistance of the antenna conductor be attained The .fact thata waver-may which-0A represents aplan or top view of along loaded that the-source ofv waves is trical .potenti l the circuit. to a point A. By radiation-point O becomes the center of a disturbance of like form which emanates in all directions through space, If the space velocity i. 6-, the velocity of free electric waves is such that diated in thewave is;propagateds' lbn 'th y t at the same velocity,

are continuously to shorten the v be inade to iltrgwelover aIcircuit withjayelocity greaterthan that of free electric wavesorlight, may bemade'use of'in directive transmission Referring'to Figure 5"in the radiated wave travels a distance OB". during the time that the gu-idediwave travels the distance 0A, tliewavefront of the nadiiated wave in the spacesurrounding'the" an-: tenna-will take the directions and The direction of propagation of the rad-i ated wave being: perpendicular tothisiront is indicatedlby'the arrows. Tlie angle-be dently depends upon the ratio'of'the' guided wave. velocity to the free wave-velocityifllf right angle triangles are drawn similarly" to Fig;- 5 forthecase where the bases-OK equals the radii OB andOG, the hypoth'enus'esi 1X3 andi A 611 will be in finitely short andat right angles: to the base 0A.. This illustrates the: critical case inwhich the ratio o'f-V velocities- .tween this Wit-V0 front and the: antenna evi is= unity; then this ratio is unity, the wave Willi accordingly be propagatednhthe hreetion ofi. transmission along the circuit;f1-.ie.,;

'Ehe" physical basis for the phenomenon when the ratio is'unity is made-readily apparentby' noting that as the wave" is rathe. direction-of antenna since 1 new centers ofi'oseill'ation beingestablish'ed' on" the wavefrontwhichintunn givesrise to"wave Y which travel in the direction O'A; coincidentally with those from theori'ginal' wavesource- O and having the-same" phase. 7 Th'cre accordingly results arecnfm'cinu of thegw-a've" in the direction 0A. Theoriginal wave-and,vv

the waves radiated from tl'resecentersofi oscillation in the' oppositedirection are opposed inphase and mutuallyextingi'iisli 'eachv other. Whenthe ratio is infinite thc' wave front will obviously be. parallel 'to thecon ductor and the direction of propagation: be perpendicular to the antenna. W lihcnthis ratio is less than unity; theantenna is not directive. i k

In Figure shown as comprising: series resis'tancc' and capacity; That the terminating impedance may be closely approximated by resistance 7 alone will be evident from a consideration.

of the specification of United Statespatent wave" should heof: uniforms intensity throughout its wave front. ."Ilhis' requires that the radiation in powersliould? bethe".

same for each unit length along tlie'lfinc. In 1 a line having uniform: resistance; inductanccyand capacity; the current'- decreases logarithmically, and the: radiation willac cordihgly be non uniform." I Ifthe'energy'is 1 to be uniformlyradiated,theremainirfgfgm X orgy in the guided carrier .waveshou crease uniformly from-thet'ermni'aIiO of the antenna to the terminal A1 where-there- 'mainder of the energy should bewabsorbe'd by the terminating impedance" In order lOO will i 4, the terminz'ltingrv element Z is a "to Heismg 1513 483, patented August I9 I ,1919. v

In order to secure best results-, tlie li-rected to secure an energ distribution of this character as illustrated .by line 7 of Figure 0, the current along the circuit must vary as the square root of the energy as represented by curve 8 of Figure 6. In order that the radiated power may be uniform along the line with decreasing current, it will be evident that the radiating constant of the antenna or its radiation resistance must be gradually increased along the line. It should vary according to the reciprocal of the square of the current amplitude, as indi- ,cated by curve 9 of Figure 7 which represents the radiation coefficient or radiation resistance. Since the radiation resistance varies approximately as the square of the height of the line, this variation in resistance may be secured by varying the height of the line so as to make this height approximately proportional to the square root of the required radiation reslstance. This is indicated in Figures 2 and 4 in which the height of the line increases from the source to the remote terminal in accordance with the requirement just stated. The gradually increasing height with decreasing current will produce uniform radiation throughout the length of the conductor. Inasmuch as the energy remaining at A is absorbed in the terminating network Z, it is possible to terminate the line at such a point that the height of the antenna will not, because of the very small current, be required to exceed practical limits in order to' maintain constant radiation.

With an antenna of varying height and a constant size conductor, the inductance and capacity per unit length will change. It ispossible to progressively vary the magnitudes of the loading reactances along the line so as to maintain the wave velocitycom stant. As an alternative method the diam eter of the conductor itself may-vary progressively with the height. lVit h this latter arrangement the loading inductances and capacities' may remain the same per unit wave length if a constant wave velocity is to be maintained throughout the length of the con ductor. -Fig1ires 2 and; indicate a variation in the diameter of the conductor to maintain the capacity per unit length substantially constant.

Figure. 8 shows a complete radiation curve with the wave amplitude as a function of its angular direction from a particular loaded line antenna of twelve times the wave length. Tlheposition and direction of extension of the antenna is indicated by the arrow. The principal energy falls within a sector of a 14 angle marked 1,. Small amounts fall in other directions due to interference. Increasing the length of the antenna to twenty-four wave lengths would 48,000 to 52,000cycles. In a system of thisv kind these various frequency waves will travel along the loaded antenna with different velocities due to the fact that the effective inductive reactance or effective capacitive reactance per unit length changes with frequency. If a carrier wave of 50,000 cycles frequency is radiated from an antenna twelve way e lengths long, at a 45 angle, as shown by the curve of Figure 9, the 48,000 and 52,000 cycle frequency waves will be spread out in different directions, as shown by curves a and b respectively of the same figure. In this case the dispersion is not particularly harmful as there is sufficient amplitude of both of the extreme frequency Waves occurring in the 45 angle direction to give a very good signal. Similary, if waves of this frequency are radiated in a 25 direction, as shown in the same figure, there will be a good quality of speech transmitted from the energy produced over an angle several degrees in Width. If, however, the transmission angle is 60, as shown in the same figure, the 52,000 and 48,000 cycle Waves overlap very slightly and a change in quality is apt, to result. In Fig. 9, the position and direction of extension of the antenna is indicated, for the respective directions of maximum directivity, in a manner. similar to that of Fig. 8.

The transmission angle depends upon the propagation velocity. A larger transmission angle accordingly requires a larger propagation velocity which in turn causes a larger difference between the propagation velocities along the line, of the different. frequency components. Accordingly the differences in direction of the various fre quency components, are accentuated as the transmission angle of the band as a whole is increased. If waves of frequencies lower than 50,000 cycles these variations will become still larger and it is, therefore, of advantage to use high carrier frequencies.

As is diagrammatically indicated in:"Figi which parallel directive antennae 20 and 21 are so spaced that their respective energy transmissionloops 22 and 23 from the terminals 24; and 25 connected with the are used as a carrier,

source extend in the same direction, and neutralize in space. If energy of the same phase is Simultaneously sup lied at points 24--a-nd 25, and if these polnts are a half wave length apart in one direction in which their respectiveantennze radiate most powerfully, ,the effect of the energy radiated from point 25 will be to oppose and neutralize that-radiated from point 24 in this direction. This is for the reason that for all points in space in this direction these radiated energies will be opposite in phase. In other words loop 22 will neutralize loop 23. If the distance between the points 24 and 25 does not correspond to a half wave length, the phase of the energy supplied to one of the antennae may be so shifted by a variable impedance device 30 that the points 24 and will tend to radiate energies which willneutralize inspace in the direction of the loops 22 and 23 This will leave only the loops 26 which are similarly directed and which are additive. If it is desired to focus on a distant station, the'directive antenna may be curved in direction as indicated in Figure 11 in which the two curved antennae 27 and 28 are each given such curvature as to focus the radiated energy on a receiving station at 29 In eneral, 1n the case of curved antennae it W111 be possible to obtain only roughly approximate neutralization'by the use of two antennae. Certain speclal cases, 'as'for example, that where the antennee extend alongarcs of concentric circles and are arranged to focus their radiated energy at the center ma give fairly exact neutralization.

X focussing effect could also be obtained by increasing the wave propagationvelocity along the line so that in the'region of one terminal of the line, the wave will be propagated at a greater rate than in the reglon of the other terminal. The operation of this will be clear from aninspection of Figure 12, in which an antenna 0A is so loaded that a wave of given frequency applied at 0 will be propagatechin the first unit of time from O to M, inthe second 4 unit from M to N, in the third unit from N toA. Suppose that each ortion OM, MN,

and NA is, throughout its ength, composed of like recurring sections. If the propagatignvelocity of the unguided waves when fradiated be OS per unit of time the radiated wave from portion OM w1ll have a front, the direction of propagation of which isindicated by arrow P, The direction of ,tliegradiated Wave of portion MN will be as indicated by Q, and that from portion NA as indicated by R. If the loading is made to progressively vary so that the wave length progressively varies, asmoothly curved wave front will obviously result.

Figure -13 indicates diagrammatically an antenna loaded in this manner by a progresresidual unradiated energy sively closer spacing of the loading capacity or shunt inductance elements, or both. Instead of closer spacing of capacity elements of the same size the capacitances of the successively capacity elements may be progressively smaller, thus giving the same,

series capacity effect. In a similar manner instead of closer spacing of the shunt inductance elements, the shunt inductance elements may be uniformly spaced and their reactances may be progressively dimished in magnitude.

A desirable form of loaded antennae .is shown in Figure 14 in which the two antennae 31 and 32, which maybe either straight or laterally curved according to the arrangement of Figures 10 or 11, are arranged with corresponding points equidistantly spaced.

A source 33 supplies energy to both these antennae over parallel circuits one of which includes a phase changing device 34. This serves, as in the arrangement of Figure 10, to maintain the ener ies emitted from corresponding points 0 the two antennae at the proper relative phases such that the energy radiated from one antenna will neutralize that radiated from the other in one direction. Eachantenna comprises both series capacity and shunt inductance load ing, thus combining the arrangement of Fig-,

' ures 2 and 4. The antennae are progressively varied in height from the source to their remote terminals in order to maintain constant the energy radiated per unit length. Each antenna terminates in an impedance element Z which is designed to absorb the mote terminal. I

Figure 15 illustrates a section of an antenna circuit loaded for waves of two different frequencies. L, and C indicate respective series inductance including the natural inductance of the circuit and series capacity which together give a capacity reactance at one of the desired frequencies.

The shunt path L C C; does not affect current of this desired frequency, since L and (l constitute an antiresonant loop hav- I ing substantially infinite impedance at that one frequency. The shunt path may, therefore, be regarded as open for the frequency considered. For current of a second -frequency, the path L (L is conductive and the net reactance of the whole unit at this frequency may be varied by varying G so as to give any reactance desired for'the reoond frequency current. Of course, an additional reaching the re.-

shunt path such as L Q, C, could be used i for another frequency by shunting such a path about condenser 0 and including in it a tuned loop or antiresonant circuit to exclude current of the second frequency. In'this manner, the number of different frequency currents may be increased as much as desire Figure 16 represents a circult havmg two This circuit may accordingly replace that of Fig. 15. Its exact adjustment is, however, considerably more diflicult.

Figure 17 illustrates an adaptation of the principle of Figure 15 applied to shunt inductance loading. L represents a unit shunt loading inductance designed in accordance with the principles previously laid down for currents of one given frequency. The anti resonant loop tuned to this one frequency effectively cuts off the other shunt paths for such currents. The loop 35 admits currents of the second frequency and a variable in ductance L permits the network L 35, L to give the proper inductive reaotance for the second frequency current. Loop 36 in the third path is antiresonant to and effectively excludes currents of the second given frequency for which variable inductance L provides the desired reactance. It conducts a third frequency for which L together with the rest of the network may determine the desired reactance.

Figure 18 illustrates a receiving system with progressively changing loading elements. The conventional receiving element is'coupled to the antenna in the ordinary manner and is preferably designed to introduce therein the proper terminating resistance to avoid reflection loss in accordance with the principle previously stated.

Figure 19 shows a multiplex transmitting system equipped with three carrier wave sources and an antenna loaded in the manner of Figure 17. Transmitting keys are associated with two of the sources and a microphone with the third, but it is to be understood that these are merely representative of any desired arrangements for modification of the carrier waves.

- Throughout the specification the various features of the invention have been explained from the standpoint of radiation at a transmission station. The principles of wave absorption are in general the same as those of wave radiation. It is, therefore, to be understood that the various features of the invention are equally applicable to receiving systems and the various circuit diagrams may each be considered as representations of a receiving system with the simple substitution of receiving apparatus for the carrier wave source.

In the appended claims the transfer of energy either by radiation from an antenna to the ether or by absorption from-the ether to the antenna'is analogous to the transfer of energy between media of different characteristics. In telephone parlance the term transducing is commonly used to describe generally a transfer of energy Without limitatiou as to the nature of the transfer.

sion, utilizing a source of carrier waves and a linear radiating conductor connected therewith, which comprises the steps of ra-.

diating a portion of the waves from said source into space, transmitting another portion of said waves along the conductor, absorbing a portion of the energy thus transmitted at points in the conductor, radiating the absorbed energy from said points and preventing reflection of the unabsorbed transmitted waves at the remote terminal.

2. The method of wave transmission which comprises radiating from a conductor very long with respect to the wave length of the radiating energy an amount of energy per unit length of .said conductor sub- -stantially uniform throughout the entire length of said conductor.

3. The method which comprises propagating an electric wave along a linear conductor at a wave propagation velocity exceeding that of light and radiating a substantially uniform amount of wave energy from each unit length of said conductor.

4. The method of directive radio transmission, utilizing a conducting element, which comprises propagating said waves along the conductor, causing the propagated velocity to differ in a systematic manner at different points in said conducting element,

absorbing a portion of the energy from the wave propagated thereaeross at each element of the conductor, and radiating said absorbed energy a The method of directive transmission comprising propagating waves along a conduct-or at a velocity exceeding that of light and progressively varying the Velocity of propagation throughout the length of the conductor.

6. The method of electric wave transmission, using a long conductor, which comprises supplying periodic energy to said conductor and propagating it at progressively increasing velocities throughout the length of the conductor. 1

7. A loaded circuit having loading reactances progressively varying in magnitude throughout its length so as to vary the wave propagation velocity for waves of a given frequency.

8. A directive transmitting antenna comprising a loaded circuit having its loading constants so adjusted that waves of a given frequency are propagated thereover at a velocity exceeding that of light and a terminating impedance connected thereto for ,ab-

sorbing, without reflection, energy transmit the wave form of said energy at a velocity exceeding that of light and a terminating impedance connected to said antenna to prevent retransmission of energy back to said means.

11. In combination, a long horizontal antenna, a source of periodic energy associated therewith for supplying energy thereto, and means for causing said antenna to radiate a uniform quantity of the supplied energy per unit lengthof the antenna.

12. In combination, along antenna,1neans connected to one terminal thereof for supplying periodic energy thereto, and means for changing the radiation resistance of said antenna progressively throughout its length so as to keep the quantity of radiated energy constant per unit length.'

13. An antenna, means for supplying a periodic wave'of a given frequency thereto and means for progressively varying the wave propagation velocity of said antenna whereby the radiated energy of said wave may be directively focussed upon a distant point.

14. A conductor curved upwardly through out its length, and means for'so loading said conductor as to cause it to radiate energy directiv'ely throughout its length.

15. A method of. directive radio t ansmis- ,sion, utilizing a source of carrier waves and a linear radiating conductor connected therewith, which comprises the steps of radiating a portion of the waves of said source into space, transmitting another portion of said waves'along the conductor, absorbing a portion of the energy thus transmitted at points in the conductor, radiating the absorbed energy from said points, neutralizing the radiation from said conductor in one direction, and preventing deflection of the unabsorbed transmitted waves at the remote terminal. I

16. The method which comprises propagating an electric wave along aklinear conductor at a wave propagation velocity exceeding that of light, radiating a substantially uniform amount of wave'encrgy from each unit length of said conductor, and'neutralizing the radiation from said conductor in one direction.

17. The method of directive radio transmission, utilizing a conduct ng element, which comprises propagating said waves along the conducting clement, causing the propagated velocity to differ in a systematic manner at different points in said conduct' ing element, absorbing a portion of the energy from the wave propagated thcrcacross at each element of the conducting element, radiating said absorbed energy, and neutralizing the radiation from said conducting element in one direction. y

18. Themethod of directive transmission comprising propagating waves along a con- I ductor at a velocity exceeding that of light, progressively varylng the velocity of propagation throughout'the length of the conductor, and neutralizing the radiation from the conductor in one direction.

19. A loaded circuit having loading reactances progressively varying in magnitude throughout its length so as to vary the wave propagation velocity for waves of,a given frequency, whereby said circuit tends to radiate directivcly in lateral directions, and means for neutralizing the radiation in one of said directions.

20. A directive transmitting antenna comprising a loaded circuit having itsloading -constants so adjusted that waves of a given frequency are propagated thereover at a. velocity exceeding that of light, whereby said circuit tends to radiate directively in lateral directions, a terminating impedance connected to said circuit for absorbing, without reflection, energy transmitted to said impedance, and means for neutralizing the radiation in one of said directions.

21. A loaded circuit having loading-reactances progressively varying in magnitude through its length so as to vary the wave propagation velocity for waves of a given frequency, whereby said circuit tends to radiate directively in lateral directions, and means for neutralizing the radiation in one of'said directions, said means comprising a second loaded circuit arranged in parallel loaded circuit witlr respect to said source,

and including a phase shifting means,

whereby the energies supplied to said loaded circuits have a desired phase difference.

In witness whereof, I hereunto subscribe my name this 13th day of May A. D.-, 1921.

' RAYMOND A. HEISING. 

